在Android上使用.NET MAUI进行手势操作时,可能会发现滑动手势不起作用或者出现其它异常.
下面给出一个定义一个自定义Renderer,在其中使用GestureDetector和OnTouchListener来自定义手势操作。
public class MyPanGestureHandler : ViewRenderer
{
    private readonly GestureDetector _gestureDetector;
    private bool _disposed;
    public MyPanGestureHandler(Context context, PinchImageView element) : base(context)
    {
        _gestureDetector = new GestureDetector(Context, new GestureListener(element));
    }
    protected override void OnElementChanged(ElementChangedEventArgs e)
    {
        base.OnElementChanged(e);
        if (e.OldElement != null)
        {
            SetOnTouchListener(null);
        }
        if (e.NewElement != null)
        {
            SetOnTouchListener(new TouchListener(_gestureDetector));
        }
    }
    protected override void Dispose(bool disposing)
    {
        if (_disposed)
        {
            return;
        }
        if (disposing)
        {
            SetOnTouchListener(null);
        }
        _disposed = true;
        base.Dispose(disposing);
    }
    private class GestureListener : GestureDetector.SimpleOnGestureListener
    {
        private readonly PinchImageView _element;
        public GestureListener(PinchImageView element)
        {
            _element = element;
        }
        public override bool OnScroll(MotionEvent e1, MotionEvent e2, float distanceX, float distanceY)
        {
            _element.PanGesture?.Invoke(_element, new PanUpdatedEventArgs(GestureStatus.Running, distanceX, distanceY));
            return true;
        }
        public override bool OnFling(MotionEvent e1, MotionEvent e2, float velocityX, float velocityY)
        {
            _element.PanGesture?.Invoke(_element, new PanUpdatedEventArgs(GestureStatus.Completed));
            return true;
        }
    }
    private class TouchListener : Java.Lang.Object, IOnTouchListener
    {
        private readonly GestureDetector _gestureDetector;
        public TouchListener(GestureDetector gestureDetector)
        {
            _gestureDetector = gestureDetector;
        }
        public bool OnTouch(Android.Views.View v, MotionEvent e)
        {
            return _gestureDetector.OnTouchEvent(e);
        }
    }
}
  此示例演示了如何在.NET MAUI中处理滑动手势。请注意,将上述代码示例中的PinchImageView替换为你正在使用的视图类型。